Disc type press

ABSTRACT

A disc type press for expression of liquid from suspensions of particle material comprising substantially coaxially mounted press discs adapted to be urged towards one another while rotating in the same direction and defining a progressively constricted pressing interspace between the discs. The material to be dewatered is introduced at the space where the interspace between the discs is relatively wide and squeezed when passed to the place of narrowest spacing between the discs. In order to increase the capacity of the press without any appreciable increase of the outer dimensions of the press and of the structural elements absorbing the stresses produced by the pressing forces, at least one additional central press disc is inserted between the outer press discs. Preferably the additional press disc or discs are mounted axially displaceable on a shaft carrying the outer discs.

United States Patent [191 Reinhall Nov. 27, 1973 DISC TYPE PRESS [76] Inventor: Rolf Bertil Reinhall, Killingevagen,

l6, Lidingo, Sweden 22 Filed: Nov.22, 1971 21 App'i. No.: 200,986

[30] Foreign Application Priority Data Messing lOO/ 158 C Primary Examiner-l-larvey C. Homsby Assistant Examiner-Philip R. Coe Att0mey-Eric Y. Munson et al.

[5 7] ABSTRACT A disc type press for expression of liquid from suspensions of particle material comprising substantially coaxially mounted press discs adapted to be urged towards one another while rotating in the same direction and defining a progressively constricted pressing interspace between the discs. The material to be dewatered is introduced at the space where the interspace between the discs is relatively wide and squeezed when passed to the place of narrowest spacing between the discs. In order to increase the capacity of the press without any appreciable increase of the outer dimensions of the press and of the structural elements absorbing the stresses produced by the pressing forces, at least one additional central press disc is inserted between the outer press discs. Preferably the additional press disc or discs are mounted axially displaceable on a shaft carrying the outer discs.

8 Claims, 2 Drawing Figures FIELD OF THE INVENTION material.

THE PRIOR ART Earlier known constructions of this type of presses comprise normally two perforated and substantially coaxially mounted press discs, which are urged towards one another at a slight angle relative to one another to form an opening therebetween and which are rotated in the same direction.

The material to be dried or dewatered is introduced between the discs ata zone where the interspace between them is relatively wide and is dewatered during rotation of the discs as it is being progressively squeezed down to the narrowest zone of the interspace from which it is subsequently removed. The shafts of the discs are usually substantially horizontal and the widest zone of the interspace, the. so-called gap, is located above the shafts whereas the narrowest zone of the interspace is located below said shafts.

OBJECTS OF THE INVENTION The principal object of the invention is to increase or even double the capacity of the presses without any appreciable increase of the outer dimensions of the presses and without substantially increasing the mechanical stresses on the structural parts which absorb the press forces arising during the operation of the presses.

STATEMENT OF THE INVENTION According to one main feature of the invention the disc press comprises a multiple of perforated, substantially coaxially mounted, rotatable press discs. The principal structure and method of operation of the press is principally the same as that of previously known structures having two uni-directionally rotating press discs, the difference being thatin the press structure operating according to the invention one or several rotatable central pressing discs have been inserted between the two outer press discs by which produced press forces are absorbed.

The apparent advantage with this novel construction resides in the discovery that the mechanical stress on the outer press discs, which absorb the pressing forces, is not increased simultaneously as the dewatering capacity of the press is increased in direct proportion to the additional dewatering discs located between the outer discs.

SHORT DESCRIPTION OF THE DRAWINGS The structure operative according to the invention shall be described hereinafter with reference to an embodiment shown by way of example in the accompanying drawing, of which:

FIG. 1 is a partially sectional view of a press constructed according to the invention and viewed in the direction of the'diameters of the press discs and FIG. 2 is a view of thepress in the axial direction of the press discs.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, reference numeral 50 denotes the base of the press which has two outer press discs 12 and 14 mounted rotatably and having between them a press disc 16 formed with perforations on both of its faces and which is freely rotatable together with said outer press discs. All press discs 12, M and 16 are rotatably mounted in bearings on a non-rotatable shaft 20.

. The two outer press discs 12 and 14 are rotatably supported on said shaft 20 by means of bearing housings 30 and 32, which are connected to the outer press discs, each housing containing a pair of bearings 40 and 42.

The axial forces produced in the operation of the press between the press discs 12 and 14, which forces tend to displace the press discs 12 and 14 in a direction away from one another, are absorbed in the shown embodiment by a hydraulic pressure fluid, such as oil,

which is supplied to the space within the bearing housing 30 adjacent one side of a stationary piston 22 fixed to the shaft 20 and which fluid is under such a pressure so that the aggregate resultant axial forces acting in a direction towards the rotating discs completely outbalance the above-mentioned separating forces. Said pressure fluid is introduced through one or several channels 24 formed in the shaft 20. When it is desired to displace the press discs 12 and 14 away from one another, the pressure fluid is supplied by the channel 26 to the space at the opposite side of the piston 22.

The shaft 20 carrying the pressure discs is supported on two brackets 52 and 54 fixed to the base 50 of the press. The shaft 20 carrying the press discs is constructed in such a manner that the two outer press discs 12 and 14 relative one another as well as relative to the intermediate dewatering disc 16 form a suitable angle in order to produce desirable conditions of compression during the passage of the material to be dried through the press.

.The shaft 20 is furthermore so constructed that the pressure disc 16 located between the two outer press discs 12 and 14, and which also in journalled on the shaft 20, will be positioned in a plane which divides the angle formed between the two outer press discs 12 and 14 in equal parts.

As indicated, the central press disc 16 is rotatably supported on the central portion of the shaft 20 by means of sliding bearings 44 or other bearing structures in such a manner as shown by way of example in FIG. 1 that it can be displaced unobstructed in axial direction in the, interspace between the two press discs 12 and 14.- By providing for free axial displacement of the central press disc, the advantage is obtained that the axial forces produced in the two'narrowest or nip zones formed between the press discs M and 16 and 12 and 16, respectively, always will fully outbalance one another as far as the effect of said forces on the central press discs is concerned.

In the space adjacent the shaft 20 between the two outer press discs and the central press discs is a flexible embodiment the form of resilient bodies made of rubber or plastic which in the assemblage of the press are precompressed to such a degree that they effectively prevent expressed liquid or dewatered material from penetrating towards the shaft 20.

In order to reduce the friction between the annular sealing rings 60 and 61, respectively, and the shaft 20 and also in order to lubricate the bearings 44 of the central press discs, lubricating oil is supplied under pressure through a lubricating channel 28 formed in the shaft 20.

The two rotatable outer press discs 12 and 14 are rotated by means of driving devices connected to each of the rotating discs and may have the form of sprocket or chain driving means 34 and 36. The two driving motors 38 and 39 may operate separately or be coupled together mechanically or electrically provided, however, that the two outer grinding discs always must rotate with identical speeds.

The central press or dewatering disc 16 in this embodiment is not driven but brought to rotate idly by means of power transmission through the annular sealing rings 60 and 61 during the working operation of the press by the compressed material to be dewatered.

The liquid suspension of the material to be dried in the press is fed into the press through two inlet openings 70 and 71 formed in the cover 76 of the press and located where the interspace between the press discs has its maximum width A. The supplied material to be dried is compressed by rotation of the press discs towards maximum compression at the place where the interspace between the press discs attains its minimum width B; from this place the dewatered material entrained between the discs is conveyed upwards towards the discharge opening 73 of the press.

The liquid expressed from the dried material is discharged through apertures 75 in the perforated surfaces of the press discs. From the outer press discs 12 and 14 the expressed liquid is discharged by free flow through drainage holes 56 formed in the lower portion of the cover 76 of the press while liquid expressed adjacent the central press disc 16 escapes through outlet I channels 18 formed in the outer periphery of the press disc 16 and drainage holes 58 formed in the lower portion of the cover 76 of the press.

The embodiment of the invention shown and described here can be modified in various manners. Thus, it is possible to mount the central press disc 16 axially undisplaceable on the shaft 20 and mount the outer press discs 12, 14 axially displaceable so as to outbalance the respective forces. Although only one central press disc is represented in the illustrated embodiment, it should be understood that a plurality of intermediate discs can be provided between the outer discs of which all or at least some of the discs must be freely movable axially in order to provide the required balancing of the forces. The axial pressing force can be produced between two central discs which then are axially displaceable in a direction away from one another, whereas the outer press discs may be fixed in axial direction. in this alternative embodiment either the intermediate or the outermost press discs can be the driven discs.

According to another modification of the press discs, the perforations 75 may open into individual cells separated peripherally from one another and preferably have the form of sectors, and each having at least one individual outlet passage for discharge of expressed liquid from the associated cell during a fraction only of each revolution of the discs. These outlet passages can suitably be connected with a suction source for assisting in the removal of theliquid by suction out of the cells.

While one more or less specific embodiment of the invention has been shown and described, it is to be understood that this is for purpose of illustration only, and that the invention is not to be limited thereby, but its scope is to be determined by the appended claims.

What is claimed is:

l. A dewatering press of the character described comprising:

a. a housing having an inlet and terial to be treated;

b. a pair of outer perforate discs rotatably supported in said housing having confronting faces arranged at an angle to one another and defining a dewatering zone therebetween in which the material is progressively compressed as it is conveyed during the rotation of the discs from an interspace of maximum width to an interspace of minimum width;

c. at least one intermediate disc spaced between said outer discs and adapted to rotate therewith as the material is being compressed between the discs and dividing said dewatering zone into two parts;

d. said outer discs and said intermediate disc being movable axially relative to one another;

e. means for driving at least one of said discs, and

f. pressure means producing a compressive force to maintain said discs in forced engagement with the material.

2. The press as claimed in claim 1 characterized in that the intermediate disc is axially displaceably mounted on a shaft (20)..

3. The press as claimed in claim 2, characterized by compressed annular sealing members (60, 61) of resilient material mounted between said discs (12, 14, 16), said annular sealing members being disposed to engage the shaft (20) and to seal off the dewatering zone and effective by the produced forces of compression to prevent liquid from penetrating to the shaft carrying the rotatable discs.

4. The press as claimed in claim 1, characterized in that the two outer press discs (12, 14) are coupled to hydraulic control members (22) permitting displacement of the press discs from one another on overload developed within the press.

5. The press as claimed in claim 1, characterized by a central shaft (20) passing through the various press discs and carrying the same and devised to absorb all produced pressing forces.

' 6. The press as claimed in claim 5, characterized in that the intermediate disc are mounted on the central shaft (20) freely rotatable and freely axially displaceable.

7. The press as claimed in claim 1, characterized in that at least one outer press disc is axially displaceable for adjustment of the compression forces inside the press.

8. A dewatering press according to claim 1, in which the pressure means is effective to balance the aggregate disc separating forces produced by the material as it proceeds from the interspace of maximum width to the interspace of minimum width.

l ll i an outlet for the ma- 

1. A dewatering press of the character described comprising: a. a housing having an inlet and an outlet for the material to be treated; b. a pair of outer perforate discs rotatably supported in said housing having confronting faces arranged at an angle to one another and defining a dewatering zone therebetween in which the material is progressively compressed as it is conveyed during the rotation of the discs from an interspace of maximum width to an intersPace of minimum width; c. at least one intermediate disc spaced between said outer discs and adapted to rotate therewith as the material is being compressed between the discs and dividing said dewatering zone into two parts; d. said outer discs and said intermediate disc being movable axially relative to one another; e. means for driving at least one of said discs, and f. pressure means producing a compressive force to maintain said discs in forced engagement with the material.
 2. The press as claimed in claim 1 characterized in that the intermediate disc is axially displaceably mounted on a shaft (20).
 3. The press as claimed in claim 2, characterized by compressed annular sealing members (60, 61) of resilient material mounted between said discs (12, 14, 16), said annular sealing members being disposed to engage the shaft (20) and to seal off the dewatering zone and effective by the produced forces of compression to prevent liquid from penetrating to the shaft carrying the rotatable discs.
 4. The press as claimed in claim 1, characterized in that the two outer press discs (12, 14) are coupled to hydraulic control members (22) permitting displacement of the press discs from one another on overload developed within the press.
 5. The press as claimed in claim 1, characterized by a central shaft (20) passing through the various press discs and carrying the same and devised to absorb all produced pressing forces.
 6. The press as claimed in claim 5, characterized in that the intermediate disc are mounted on the central shaft (20) freely rotatable and freely axially displaceable.
 7. The press as claimed in claim 1, characterized in that at least one outer press disc is axially displaceable for adjustment of the compression forces inside the press.
 8. A dewatering press according to claim 1, in which the pressure means is effective to balance the aggregate disc separating forces produced by the material as it proceeds from the interspace of maximum width to the interspace of minimum width. 